ncu --doctor show the help about npm-check-updates HOT 3 OPEN

ncu --doctor is intended to show the help. The -u modifier is required to write upgrades in doctor mode, just as ncu -u is required to write upgrades normally.

from npm-check-updates.

As i understand, sorry my bad english from your documentation:

So to use i have to run:
ncu --doctor

similar to simulate what would happen...and then ncu --doctor -u to REALLy install/upgrades marked or tested without any problems...

Thanks

from npm-check-updates.

Yes, I could see how that could be confusing. I've modified the documentation as follows:

Usage:

ncu --doctor -u
ncu --no-doctor
ncu -du

Iteratively installs upgrades and runs your project's tests to identify breaking upgrades. Reverts broken upgrades and updates package.json with working upgrades.

Requires -u to execute (modifies your package file, lock file, and node_modules)

from npm-check-updates.